1. Field of the Invention
The present invention relates to a working mechanical device for opening and closing a pair of end effector bodies with a power transmitting mechanism for performing certain treatments on a living body tissue, and a manipulator having such a working mechanical device on its distal end for performing manipulating actions from the other end thereof through an arm or the like.
2. Description of the Related Art
According to laparoscopic surgery, it is customary to form a plurality of holes in the abdominal part of the patient, insert an endoscope and a manipulator (or forceps) into the respective holes, and perform the surgical operation while images captured by the endoscope are being observed on a display monitor by the surgeon. Since such a laparoscopic surgical operation does not require the abdominal cavity to be opened, the burden on the patient is small and the number of days which the patient needs to recover and spend in the hospital until they are allowed to come out of hospital is greatly reduced. For these reasons, the laparoscopic surgical operation is expected to find an increased range of applications.
Manipulators for use in laparoscopic surgery are desirably capable of quick and appropriate surgical techniques depending on the position and size of the affected region, and are used to perform various surgical techniques like suture, ligature, knot-tying and removing of the affected part of the patient. The present applicant has developed and proposed a manipulator which has a high degree of freedom for manipulation and which can easily be operated (see, for example, Japanese patent No. 3631450).
The manipulator disclosed in Japanese Patent No. 3631450 includes a working unit having a pair of end effector bodies on its distal end which can be opened and closed symmetrically with respect to a reference axis. The working unit has a wide operating range, can operate in the same fashion as general tools such as pliers or the like, and can easily be manipulated.
With the working unit of the manipulator disclosed in Japanese Patent No. 3631450, the pair of end effector bodies is actuated by respective independent mechanisms to open and close grippers about an opening/closing axis and rotate the grippers about an attitude axis. Specifically, when the grippers are turned in mutually opposite directions, the grippers are opened and closed, and when the grippers are turned in the same direction, the grippers are rotated. However, the grippers are opened and closed and are rotated in the same plane. For example, when the grippers are opened and closed in horizontal directions, they are rotated also in horizontal directions, and when the grippers are opened and closed in vertical directions, they are rotated also in vertical directions. Consequently, the opening/closing axis and the attitude axis of the grippers are limited in their relative layout.
In laparoscopic surgical operations, the surgeon may find it desirable to rotate the grippers in horizontal directions and at the same time to open and close the grippers in vertical directions or vise versa for better operability depending on the living tissue to be treated or how the living tissue is to be treated. It may also be preferable to open and close the grippers in any directions with respect to the attitude axis.